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  1. Qt
  2. QTBUG-87330

QList - double performance drop

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Details

    • Bug
    • Resolution: Done
    • P3: Somewhat important
    • 6.0
    • 6.0.0 Alpha
    • Core: Containers and Algorithms
    • None
    • core i7-8700
    • Windows
    • 8
    • Qt6_Foundation_Sprint 20, Qt6_Foundation_Sprint 21, Qt6_Foundation_Sprint 22

    Description

      This simple code show QList double performance drop for Qt 6

      QElapsedTimer timer;
timer.start();    
QList<QString> list;
int count = 1000000;
for (int i = 0; i < count; i++) {
     list.append(QString::number(i));
}    
qDebug() << timer.elapsed();

      On my machine it prints (release build):

      Qt 5.15.1: 117

      Qt 6.0 alpha: 321

      Attachments

        1. image-2020-10-14-21-15-15-976.png
          183 kB
          Andreas Buhr
        2. image-2020-10-15-02-27-47-947.png
          109 kB
          Andreas Buhr
        3. image-2020-10-15-02-29-09-196.png
          112 kB
          Andreas Buhr

        Issue Links

          relates to

          Task - A task that needs to be done. QTBUG-88484 Disentangle QString::number() from locale code

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Closed

          Task - A task that needs to be done. QTBUG-87637 Compare container performance (QList, QString, QByteArray) between Qt 5.15 and Qt 6

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Reported
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          Activity

            People

              agolubev Andrei Golubev
              n_r_w n_r_w
              Maurice Kalinowski Maurice Kalinowski
              Alex Blasche Alex Blasche
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              Dates

                Created:
                Updated:
                Resolved: